High viscosity index detergent lubricating oils



United States Patent HIGH VISCOSITY INDEX DETERGENT LUBRICATING OILS William L. Wasley, Santa Ana, and Chester E. Wilson, Anaheim, 'Calif., assignors to Union Oil Company of t( Jalifornia, Los Angeles, Calif., a corporation of Caliorma No Drawing. Application February 20, 1956 Serial No. 566,381

21 Claims. (Cl. 252-33) This invention relates to lubricating oils containing high molecular weight hydrocarbon sulfonates. More particularly, this invention relates to high viscosity index lubricating oil compositions having high detergency characteristics and consisting essentially of mineral lubricating oil containing sulfonates derived from particular hydrocarbon polymers with or without added anti-corrosion, anti-rust, anti-oxidation agents and the like.

Internal combustion engines, both of the spark-ignition and compression-ignition types, are constantly being modified to give among other improvements increased efficiency and greater horsepower output. With these changes, improvements in lubricating oils suitable for use in these engines are necessary.

One of the important characteristics of a lubricating oil if it is to operate efficiently in such engines is that it does not change greatly in viscosity with change in temperature. This viscosity-temperature relationship is measured or denoted by viscosity index (V.I.), a high V.I. oil being one that has a relatively small change in viscosity with changes in temperature. ious polymeric materials to improve the V.I. of lubricating oils is known, however the polymers which have been used have a tendency to break down in use probably because of the shearing effect in bearings, gears and the like so that the. VI. of an oil containing these materials tends to decrease when the oil is used for appreciable periods of time.

Moreover, the polymers have a tendency to deposit on heated engine parts such as the stems and tulips of intake valves where the amount of oil supplied to such parts is relatively small.

Another important characteristic of a lubricating oil which is to be used in internal combustion engines is that of detergency, i.e., the ability of the oil to prevent the formation of carbon and/or varnish-like deposits in the engine, particularly on pistons and cylinder walls, in ring grooves, in hydraulic valve lifters, and the like.

Still another characteristic of a lubricating oil suitable for use in the described engines is that it is capable of preventing the formation of and/ or the build-up of acidic bodies in the oil during use, thus greatly reducing or preventing the corrosion of metal parts in the engine.

It is an object of this invention to provide a lubricating oil having the characteristics of high viscosity index, high detergency, and being capable of preventing the formation and/or build-up of acids in the oil during use.

It is another object of this invention to provide a lubricating oil suitable for use in internal combustion engines which oil (1) has a high V.I. which does not decrease appreciably during use, (2) prevents the formation of carbon and/or. varnish-like depositsin the engine and (3) prevents corrosion in the engine.

A further object of this invention is to provide a lubricating oil having the characteristics described which consists of a lubricating oil containing a single additive material which is effective in imparting all of these characteristics.

The use of var- 2,883,340 Patented Apr. 21, 1959 It is found that a lubricating oil having all of the above-mentioned characteristics can be obtained by adding to a mineral lubricating oil between about 1% and about 10% or 15% by weight of a product obtained by polymerizing a low molecular weight olefin, e.g. isobutylene or copolymerizing such monoolefin with C to C multi-olefins, such as butadiene isoprene or the like, to produce polymers and/ or copolymers of about 10,000 to 50,000 molecular weight, preferably 10,000 to 30,000 molecular weight, sulfonating the polymer as by treatment with chlorosulfonic acid or sulfur trioxide and converting the resulting sulfonated product to its metal salt using an oxide, hydroxide or carbonate of an alkali or alkaline earth metal. Preferably the metal sulfonate salt will be one having excess metal base combined therewith either during or subsequent to the neutralization step.

Bases to be employed include the basically reacting compounds of sodium, lithium, potassium, calcium, barium, and strontium. The oxide, hydroxide, carbonate,

. etc. of one of these metals is used for neutralizing the polymer or copolymer sulfonic acid and for producing the basic or complex sulfonate. Also combinations of these metals may be used. Thus one metal base or a mixture of metal bases may be used in the neutralization step and a different metal base may be used in complexing if desired.

Monoolefins which may be employed and will produce polymers which are useable in preparing the additives of this invention include, in addition to the isobutylene mentioned, propylene, n-butylene, 2-methyl butene-l, 2-ethyl butene-l and similar olefins containing 3 to 6 carbon atoms per molecule. Of these olefins the isoor branched chain monoolefins are preferred and isobutylene is particularly preferred.

Multiolefins which may be used to copolymerize with the monoolefins to obtain copolymers which are useable in preparing the additives of this invention include isoprene, butadiene, Z-methyl 'butadiene-1,3, 2,3-dimethyl butadiene-1,3, hexadiene-2,4, cyclopentadiene, piperylene, and the like having between 4 and 7 carbon atoms per molecule. Of the multiolefius isoprene and butadiene are particularly preferred.

It should be mentioned that the relatively pure olefins and multiolefins may be used but hydrocarbon mixtures containing the olefins and/ or multiolefins may be utilized with success. In the event that the relatively pure compounds are used, it is generally necessary that they be mixed with low boiling hydrocarbons prior to reaction. A mixture consisting of isobutylene and the butanes may be polymerized to give an entirely satisfactory polymer product. Moreover butadiene fractions containing preferably 1% to 3%, but as high as 20% of butadiene, together with butanes, butylenes, etc. can be used successfully to form copolymers. Moreover, the weight ratio of multiolefin to monoolefin used in preparing the copolymers will be between about 0.5 and 10 to and preferably between 1 and 3 to 100. The copolymers of this invention are those in which the ratio of multiolefin to monoolefin is between 0.005 and 0.1 to 1 and prefera-bly between 0.01 and 0.03 to 1.

In preparing the polymers and copolymers the reaction is effected at temperatures of 40 C. to 78 C. in the presence of Friedel-Crafts catalysts. Methods described in U. S. Patent 2,356,128 result in the production of polymers and copolymers which can be further treated as described herein to produce the additive material which when incorporated in lubricating oil gives the lubricants of this invention.

While we may use polymers of monoolefins or copolymers of monoolefins with multiolefins, prepared by any known method, we prefer to prepare our polymeric materials in a continuous reactor. For example, approximately 1300 grams per hour of a normally liquid hydrocarbon solvent such as pentane, hexane, heptane, or naphtha, boiling within the limits of about 35 C. to about 175 C., are pumped into a copper coil which is cooled in a dry ice and acetone bath at 70 to 78 C. This coil, which is made of 18 feet of inch copper tubing, will be referred to as the reactor or coil reactor. Into this same reactor is introduced a stream of 400 grams of isobutylene, for example, per hour. At a point in the coil where the isobutylene and solvent hydrocarbon have been thoroughly mixed and cooled, there is introduced a stream of B1 gas in ethane, in the proportion of approximately 5 to 50 parts of ethane per part of 131 The B1 catalyzed polymerization is exothermic, and by controlling the rate of addition of the BF -ethane stream, the polymerization rate and temperature may be controlled, and, in turn, the average molecular weight of the polymer may be controlled. A thermocouple is inserted into the reactor at a point shortly beyond the site of introduction of the catalyst, and the temperature of the reaction mixture may be measured and controlled, as noted, by the rate of catalyst addition. Generally the amount of catalyst, e.g. B'F will be 0.1 to 3 parts per part of reactive olefin of multiolefin on the weight basis.

Other catalysts which may be used in place of the BF are any of the well known Friedel-Crafts catalysts, e.g., AlCl AlBr mixed aluminum chlorobromides, aluminum ethoxychloride, stannic chloride and titanium tetrachloride. Aluminum chloride or bromide or chlorobromide may be dissolved in a suitable solvent such as liquid methyl or ethyl chloride. The liquid Friedel-Crafts agent, such as TiCl are completely soluble in hydrocarbon solvents.

The syrupy solution of polymer in solvent, leaving the reactor, may be sulfonated directly or may be stored for later use. If it is to be stored, the solution is preferably washed two times with an equal volume of water and a portion of the solvent is distilled to strip out traces of water. The resulting polymer solution is clear and waterwhite. The polymer will have a molecular weight between about 10,000 and 50,000 depending on the time, temperature, amount of catalyst and the particular monoolefin employed.

It a copolymer is to be made instead of the homopolymer described above, a liquid multiolefin, such as isoprene, may be added to the liquid hydrocarbon solvent, or a gaseous multiolefin such as butadiene may be introduced into the cold coil reactor through any suitable metering device. It will be added at such a point in the reactor that it is well mixed with monoolefin and solvent before the reaction mixture is contacted with catalyst.

The preparation of a copolymer using, for example, isoprene and isobutylene, is carried out as follows. Into the reactor described above and cooled in Dry Ice and acetone, is pumped 1250 grams per hour of normal pentane containing eight grams of isoprene. At a point in the reactor after the solvent-isoprene mixture has been cooled to at least about 65 C., isobutylene is introduced at a rate of 400 grams per hour. At a subsequent point B1 ethane (1:15) is introduced at a rate of about 1.8 to 2.5 grams of B1 per hour, the reaction temperature being maintained at about 65 C. to -68 C. Under these conditions approximately 400 grams of copolymer of isoprene and isobutylene having a molecular weight of about 20,000 is made each hour. The solution is washed twice with 0.5 to 1.5 parts by weight of water and dried by distillation. There results a clear water-white copolymer solution. The above process is equally applicable to other olefins and multiolefins described herein.

Polymers and copolymers as described herein are converted to sulfonic acids by treatment under appropriate conditions with sulfur trioxide, chlorosulfonic acid or fuming sulfuric acid. Although side reactions such as sulfation may occur, the products of reaction of the polymeric materials with the sulfonation agents under the conditions described is believed to result primarily in the formation of the corresponding sulfonic acids. For this reason the products will be referred to herein as sulfonic acids and, following neutralization, as sulfonates.

One method of sulfonation which is found to form sulfonic acids of good quality which can be neutralized and converted to sulfonates or basic sulfonates as described hereinbelow is the following. The hydrocarbon polymer or copolymer is dissolved in normal pentane or other similar hydracorbon solvent to give a 10 to 15 weight percent solution. The solution is cooled to 0 C. and S0 gas is introduced in a manner such as to avoid local charring of the polymer around the bubbles of gas. This is accomplished by diluting the S0 with an inert carrier gas. Suitable gases are anhydrous ethane, anhydrous nitrogen, or other gases which are inert under the conditions employed. As an illustration, dry nitrogen gas is bubbled through liquid S0 at 20 C. to 35 C., and the mixed gases obtained are passed into the cold, well stirred, pentane solution of polymer. After the desired or calculated amount of S0 has been absorbed in the polymer solution, the solution is washed with water, cooled to about 0 C. and the resulting polymer sulfonic acid in solution in hydrocarbon solvent may be stored as such, or it may be neutralized as for example by treatment with aqueous sodium hydroxide, barium hydroxide or other suitable basically reacting alkali or alkaline-earth metal compound. The resulting mixture of polymer sulfonate, solvent, water and inorganic salts is added to a relatively low viscosity mineral lubricating oil in the proportion of one part of polymer sulfonate to two parts of a relatively low viscosity mineral lubricating oil, e.g., an SAE 5W or 10W grade oil. The oil is heated to 130 C., in a stream of inert gas such as nitrogen if desired to remove water and filtered to remove inorganic salts. In this manner there is produced a clear, very viscous solution of polymer sulfonate in oil. This solution when added to lubricating oils imparts detergent and high V.I. characteristics. The solution of sulfonate in oil will be referred to herein as additive concentrate.

A more convenient method of sulfonating the polymer or copolymer is through the use of chlorosulfonic acid. For example, a solution of grams of a copolymer of approximately 2 wt. percent isoprene and 98 wt. percent isobutylene having a molecular weight of about 18,000 dissolved in 900 ml. normal pentane is cooled to 0 C. The solution is stirred vigorously while 3.5 grams of chlorosulfonic acid is added dropwise. After 30 minutes to 1 hour of stirring at 0 C., the pentane solution of sulfonated copolymer is poured into a well stirred mixture of 200 grams of a light mineral lubricating oil, and 5.6 grams of Ba(OI-I) dissolved in 40 ml. of hot water or the equivalent amount of other alkali or alkaline earth metal base is added. The resulting mixture is heated to C. in a stream of inert gas to speed up the removal of pentane and water. The dehydrated hot oil solution is filtered to yield a clear, very viscous oil solution containing approximately 35% by weight of the barium copolymer sulfonate. This additive concentrate, when added to lubricating oils in amounts indicated herein, imparts detergent and high V.I. characteristics. The proportion of polymer sulfonate in the additive concentrate is varied by varying the proportion of lubricating oil added. Generally it is preferred that this concentrate contain between about 15% and about 50% by weight of the sulfonate. A particularly satisfactory lubricating oil for this purpose is a light mineral lubricating oil having an SU viscosity at 210 F. of 38 seconds and a V.I. of 83. Such an oil is known in the art as 90 neutral oil and this terminology will be used herein.

Although mineral lubricating oils containing the abovedescribed additive material, i.e. the metal salt of sulfonic acids obtained by sulfonating hydrocarbon polymers of the type described herein, operate satisfactorily in many internal combustion engines, it is highly desirable to incorporate in the additive material a so-called alkaline reserve. When added to lubricating oil, such an additive imparts this alkaline reserve to the lubricating oil and such an oil is capable of neutralizing acids formed in the oil during use. The effect is to reduce or prevent the build-up of'corrosive conditions in the engine. Alkaline reserve is measured in terms of base number which is expressed in terms of equivalency in milligrams of KOH per gram.

Alkaline reserve is incorporated in the additives of this invention in any of several ways. When excess base is employed in the neutralization step it is found that the sulfonate product is basic in character. In another method the neutralized sulfonic acids may be heated and mixed with additional metal base in the presence of relatively small amounts of water. and the resulting product heated to remove the water. In still another method the sulfonic acids or the corresponding metal sulfonates are heated to a temperature of between 180210 F. with excess base, water and a so-called promoter, e.g., a phenolic compound, for about 0.5 to 1.5 hours and the temperature is then increased to vaporize the water. The amount of excess base so incorporated will be from about 0.1 to about 2.5 equivalents per equivalent of metal sulfonate depending upon the particular metal base employed and upon conditions under which neutralization and/ or complexing is effected. In neutralizing the sulfonic acids 1.1 to 3.5 equivalents of metal base per equivalent of sulfonic acid will be employed where complexing is desired during the neutralizing step.

In all of the above methods following the removal of water the product may be filtered as through a filtering earth and the product is found to contain excess base in'a chemically combined or complexed form which is stable and does not become insoluble or separate on standing. Prior to neutralization and/or treatment to incorporate excess base the polymer sulfonic acids may be dissolved in a light petroleum naphtha or preferably in a lubricating oil as, described hereinabove in connection with a description of the neutralization process. The amounts employed will be such that the resulting oil concentrate will contain between about 15% and about 50% by weight of the basic polymer sulfonate.

Promoters which aid in preparing the basic sulfonates, i.e., in effecting the complexing of excess base include various hydrocarbon substituted phenols e.g. p-t-butyl phenol, ethyl phenol, diethyl phenol, p-t-amyl phenol, octyl phenol, nonyl phenol, cresols, xylenols, etc. U. S. Patent No. 2,616,904 discloses many compounds which are suitable promoters for this type'of reaction when applied to sulfonates, etc., different from those described herein. It is found that the promoters described in that patent, including compounds other than phenols, may be used successfully to form the complex or basic sulfonates described herein.

The term base as used herein has its usual chemical meaning. Thus a base is used to neutralize the sulfonic acids and when excess base is used as above-described the product is a basic sulfonate. It is to be pointed out that bases described herein are the basically reacting compounds, i.e., the oxides, hydroxides, carbonates, etc. of the alkali and alkaline earth metals. It is the sulfonic acid salts and basic salts of these metals which are useful.

In preparing the final lubricating oils of this invention a suificient amount of the polymer or copolymer sulfonate-oil concentrate is added "to and mixed with lubricating oil of the desired grade to produce a finished lubricating oil having the desired detergency, V.I., viscosity, and alkaline reserve. Generally the finished oil will contain between about 3% and about 25% by weight of the additive concentrate and correspondingly between about 1% and about by weight of'the polymer sulfonate or the basic or complex polymer sulfonate.

Lubricating oils to be used as the base oil to which the additive or additive concentrate is added to produce the finished lubricating oilsof this invention include substantially any mineral lubricating oil produced from parafiinic or naphthenic base crude oils. Preferably, and in order to obtain the advantages of this invention to the greatest degree the oil will be one which has been solvent treated by any of the well known extraction methods with a selective solvent which selectively dissolves the more aromatic fractions of the oil. Typical selective solvents include phenol, furfural, benzol-SO, and the like. Lubricating oils having an initial V.I. above about or are preferred since following addition of the additive of this invention the V.I.of' the finished oil will be in the desired range of plus without the necessity of employing large quantities of the polymer. Moreover the detergency of oils containing the additive is generally higher where the base oil is one having a V1 above about 80.

On the other hand the additive of this invention is effective in improving the V.I., the detergency and the anti-corrosion characteristics of low V.I. oils, e.g., oils having V.I.s of 20 to 60 or 70. Also similar improvements, although to a possibly lesser degree, are realized with simple lubricating distillates which may if necessary be dewaxed but which are not solvent extracted.

The following specific examples are illustrative of the invention.

Example I An isobutylene polymer is prepared in the following manner. Pentane is pumped at the rate of approximately 1300 grams per hour into' a coil reactor, described hereinabove, which is maintained at a temperature of about -75 C. Isobutylene is introduced into the reactor at a rate of approximately 400 grams per hour and mixed with the pentane. Following cooling and mixing, a stream of one part of BF gas in 20 parts ethane is introduced at a rate of about 2.5 grams of BF per hour. At this rate of addition the temperature of the reaction mixture is maintained at about -65 C. to 70 C. The residence time in the reactor following introduction of the BF catalyst is about 1.05 minutes. The product leaving the reactor consists of a pentane solution of isobutylene polymer of approximately 32,000 average molecular weight.

Example 11 Example III An isobutylene fraction consisting of approximately 20% by weight of isobutylene in butanes with a small proportion of n-butylene is used in the process of Example I in place of the mixture of isobutylene and pentane and the product is a polymer having an average molecular weight of about 14,000.

Example IV Example I is repeated using Z-ethyl butene-l in place of isobutylene The product is a polymer of approxi mately 17,000 average molecular weigh Example V A copolymer of isobutylene and isoprene is prepared by introducing into the coil reactor a mixture of normal pentane and isoprenein the ratio of 1 part of isoprene to parts of pentane. This mixture is intro- L duced at the rate of approximately 1250 grams per hour and cooled in the reactor to a temperature of approximately -65 C. at a point where this temperature has been reached, isobutylene is introduced at a rate of approximately 400 grams per hour, at a subsequent point in the reactor coil a mixture of BF and ethane (approximately 1 part BF per 15 parts of ethane) is introduced at a rate of approximately 2.6 grams of BF per hour. Following introduction of the catalyst stream the residence time in the reactor is approximately 0.9 minute. The product leaving the reactor consists of approximately 400 grams per hour of the copolymer of isoprene and isobutylene in pentane solution. This copolymer has an average moleular weight of approximately 21,000.

Example VI Example V is repeated using a corresponding amount of butadiene in place of the isoprene. The product polymer has a molecular weight of approximately 24,000.

Example VII Example V is repeated using 2.4 parts of isoprene to 150 parts of pentane. The product copolymer has a molecular Weight of approximately 15,000.

Example VIII The products of Examples 1, IV and V are sulfonated using chlorosulfonic acid as thesulfonating agent. The products of these examples as obtained in pentane solution are reacted with chlorosulfonic acid in the ratio of 100 grams of polymer or copolymer present in the pentane solution to approximately 3.5 grams of chlorosulfonic acid. The mixture is vigorously stirred during the addition and for a period of approximately 30 to 60 minutes following the addition of the chlorosulfonic acid during which time. the temperature is maintained at approximately C. Following this treatment the sulfonated polymer or copolymer is added to and mixed with approximately 200 grams per 100 grams of the original polymer or copolymer of a mineral lubricating oil having viscosity at 210 F. of about 38 SSU and a V.I. of approximately 85.

The product obtained by sulfonating the product of Example I is converted to its barium salt by treatment with the chemically equivalent amount of barium hydroxide dissolved in approximately parts by weight of "hot water. The mixture is added to 90 neutral oil in the proportion of 1 part of polymer to 2 parts of oil and is heated and stirred to effect neutralization and then further heated to remove pentane and water and filtered through diatomaceous earth. The dehydrated product which is an additive concentrate in light mineral oil will be referred to hereinafter as product A.

A 1000 gram portion of product A is treated with 35 grams additional barium hydroxide and 200 grams of water, and 30 grams of p-t-butyl phenol are added prior to evaporation of the water. The product after filtration will be referred to as product B.

The sulfonated product of Example IV was mixed with 2 chemical equivalents of sodium hydroxide, added as a 40% aqueous solution, and 2 parts of 90 neutral oil per part of polymer. The resulting mixture was heated and stirred to a final temperature of 140 C. to eliminate water and the hot solution filtered. This product will be referred to as product C.

The sulfonated product of Example V (1% isoprene) is mixed with 2 parts of 90 neutral oil and reacted with 4 equivalents of barium'hydroxided added hot as a 30%. aqueous solution in the presence of 0.1 part of nonyl phenol per part of sulfonated polymer. The resulting mixture is heated and stirred for a period of approximately 30 minutes at a temperature of 100-110 C. and then further heated to 140 C. to vaporize water and the dehydrated product filtered. This product will be referred to asv product D.

8 Example [X The product of Example VII in n-pentane, is sulfonated with chlorosulfonic acid at 0 Cl, using 124 grams of chlorosulfonic acid for 1320 grams of polymer. The mixture thus obtained is neutralized with 500 grams of Ba(OH) -8H O slurried in 700 cc. of water. The mixture is diluted with 2640 grams of neutral oil and heated to remove n-pentane and water. The temperature of the oil is raised to 160 C. to assure complete removal of water. This concentrate will be referred to as product E.

Example X Lubricating oils are prepared by incorporating various percentages of the additive concentrates described as products A to E in Examples VIII and IX in mineral lubricating oil. The oil employed is a solvent treated western mineral lubricating oil having a V1. of 86 and SU viscosities of 125 seconds at F. and 41 seconds at 210 F. This oil is referred to hereinafter as base oil. Physical data for the finished oils are as follows:

Oil Base SU Vis- Seconds No. Composition N 0. V1. cosity, at 210 F.

1 Base oil 0 86 41 2 Base oil+l4% Product A 0 135 322 62 3 Base oil-{44% Product 13.... 2. 6 136 338 64 4 Base oil+20% Product 0...- 0 132 334 62 5 Base oil-{49% Product D 1. 8 216 51 6 Base 0il+18% Product D. 3. 5 137 333 64 7 Base oil+32% Product E 4. 1 60 Example XI Chevrolet engine tests are made on numbered oils described in Example X. In this test, a standard Chevrolet test engine is run for a total of 54 hours under varying conditions of load and temperature. Thus the engine is operated for 2 hours under conditions set forth in column A below, 2 hours under conditions set forth in col- The following are test results showing the effectiveness of the additives in maintaining engine cleanliness.

Oil Piston- Var- Sludge Ring N 0. Composition Rating nish Rating Plug- Rating ging Base Oil 43 63 36 21 Base Oil-+14% Product A--. 76 63 85 13 Base Oil+14% Product B 88 79 87 0 Base Oil+20% Product C 84 89 79 7 Base Oil+9% Product D 73 82 63 6 Base Oil+18% Product D... 94 94 88 2 Base Oil+32% Product E... 86 83 63 5. 7

-Piston rating is the average of the thrust and antithrust faces of 6 p1stons. Rating scale is from 0 to 100, with 100 being perfect.

Varnish rating (0 to 100, with 100 indicating complete absence of varnish) is the average of varnish on piston skirts, rocker arm cover, push rod cover, cylinder walls and crank case oil pan.

{Sludge ratmg (0 to 100, with 100 indicating complete absence of sludge) is average of rocker arm assembly, rocker arm cover, push rod cover, oil screen, crank case oil pan, push rod chamber and valve top deck.

Rmg pluggingus expressed as percent of rings plugged. Zero is a perfect score in this rating scale.

Example XII The products of Examples II, III and VI are sulfonated by treatment with S0 The products of these examples as obtained in pentane solution are reacted with 80;, introduced in a diluted form using ethane as the diluent.

:In this method anhydrous ethane is bubbled through liquid S at 20 C. to 35 C. and then into a stirred mixture of polymer or copolymer in pentane solution at 0 C. In each instance the reaction is continued until no further reaction occurs as indicated by the lack of heating in the reaction mixture. The resulting products are dissolved in a light solvent-treated mineral lubricating oil in the ratio of 2 parts of oil per part of original polymer or copolymer.

. The product obtained by sulfonating the product of Example II is converted to its calcium salt by treatment with a chemically equivalent amount of calcium hydroxide and water. The resulting neutral product is mixed with 2 parts of 90 neutral oil per part of polymer and, after heating to remove pentane and water and filtering will be referred to as product F.

A 1000 gram portion of product F is mixed with 24 grams of calcium hydroxide, 100 grams of water and 12 grams of p-t-butyl phenol and heated for 1 hour at 110 C. The so-treated product is further heated to 140 C. to evaporate water and filtered. This product is referred to as product G.

The product obtained by sulfonating the product of Example III is reacted with 3 chemical equivalents of potassium hydroxide in the presence of 0.055 part of p-t-amyl phenol and 2 parts of 90 neutral oil per part of polymer sulfonate. This neutralization and complexing reaction is effected at 110 C. for a period of about 60 minutes. This is followed by heating to 140 C. to vaporize water and pentane and then filtering. The product is referred to herein as product H.

The sulfonated copolymer of Example VI is converted to its complex strontium salt by treatment with 5 chemical equivalents of strontium hydroxide in the presence of 1 part of water and 0.1 part of p-t-butyl phenol per part of sulfonated copolymer. This reaction is eifected by heating and stirring the mixture at 30 C. for 60 minutes in the presence of 2 parts of light mineral oil per part of polymer, and then heating to remove pentane and water and filtering. The filtered product will be referred to herein as product 1.

Example XIII The additive concentrates prepared as described in Example X as products F to I are added to the base oil described in Example VIII in various amounts. The resulting finished oils have the following characteristics.

011 Base SU Vis- Seconds No. Composition No. V.I. cosity. at

1 Base oil 0 86 125 41 9 Base oil +16% Product F 0 136 318 62 10 Base 011 +18% Product G 140 329 65 11. Base 011 Product H 125 250 53 12.--" Base 011 +6% Product I. 117 149 44 13 Base 011 +15% Product 1..-. 138 319 63 Example XIV Chevrolet engine tests made on the numbered oils of Example XI are as follows. The tests are conducted in the same manner as described in Example XI.

(For footnotes (a) to (d) see table in Example XI.)

The above specific examples are to be taken as illustrative and not as limiting the invention. Thus although pentane is shown as the solvent used in the polymerization and sulfonation reaction other similar materials including mixtures of low boiling hydrocarbons are equally usable. Moreover although only limited proportions of active additive material have been shown in the specific examples it is found that amounts within the limits set forth herein are effective in imparting increased V.I., improved detergency, etc. described herein to lubricating oils. Furthermore although the specific examples show the use of the additives in but one type of mineral lubricating oil it is found that more naphthenic and more highly paraffinic type mineral lubricating oils are suitable for use with the additives described and in every case the improvements described are realized.

We claim:

1. A lubricating oil additive adapted to be diluted with mineral lubricating oil to produce a lubricating oil having high V1. and detergency characteristics, said additive consisting essentially of mineral lubricating oil containing between about 15% and about 50% of an oilsoluble metal salt of a hydrocarbon polymer sulfonic acid, said metal being selected from the class consisting of the alkali and alkaline earth metals and said hydrocarbon polymer being one having a molecular weight between about 10,000 and about 50,000 and selected from the class consisting of polymers of monoolefins having 3 to 6 carbon atoms per molecule and copolymers of said monoolefins with multiolefins having 4 to 7 carbon atoms per molecule in which the ratio of multiolefin to monoolefin is between about 0.005 and about 0.1 to l.

2. A lubricating oil additive adapted to be diluted with mineral lubricating oil to produce a lubricating oil having high V.I. and detergency characteristics, said additive consisting essentially of mineral lubricating oil containing between about 15 and about 50% of an oil-soluble complex metal hydrocarbon polymer sulfonate in which 0.1 to 2.5 equivalents of metal base is combined with 1 equivalent of metal sulfonate, said metal of the metal sulfonate and of the metal base being selected from the class consisting of the alkali and alkaline earth metals and said hydrocarbon polymer being one having a molecular weight between about 10,000 and about 50,000 and selected from the class consisting of polymers of monoolefins having 3 to 6 carbon atoms per molecule and copolymers of said monoolefins with multiolefins having 4 to 7 carbon atoms per molecule in which the ratio of multiolefin to monoolefin is between about 0.005 and about 0.1 to l.

3. A lubricating oil additive according to claim 2 in which said complex metal hydrocarbon polymer sulfonate is obtained by neutralizing the corresponding hydrocarbon polymer sulfonic acids with between 1.1 and 3.5 equivalents of metal base.

4. A lubricating oil additive according to claim 2 in which said complex metal hydrocarbon polymer sulfonate is obtained by reacting the neutral metal sulfonate with 0.1 to 2.5 equivalents of said metal base and water in the presence of a hydrocarbon substituted phenol at about 2l0 F.

5. A high V.I., detergent lubricating oil consisting essentially of mineral lubricating oil containing between about 1% and about 15 by weight of the metal salt of a hydrocarbon polymer sulfonic acid, said metal being selected from the class consisting of the alkali and alkaline earth metals and said hydrocarbon polymer being one having a molecular weight between about 10,000 and about 50,000 and selected from the class consisting of polymers of monoolefins having 3 to 6 carbon atoms per molecule and copolymers of said monoolefins with multiolefins having 4 to 7 carbon atoms per molecule in which the ratio of multiolefin to monoolefin is between about 0.005 and about 0.1 to 1.

6. A lubricating oil according to claim 5 in which said metal is an alkaline earth metal.

7. A lubricating oil according to claim in which said metal is an alkali metal.

8. A lubricating oil according to claim 5 in which said hydrocarbon polymer is an isobutylene polymer having a molecular weight between about 10,000 and about 30,000.

9. A lubricating oil according to claim 5 in which said hydrocarbon polymer is an isobutylene-isoprene copolymer in which the ratio of isoprene to isobutylene is between 0.01 and 0.03 to 1.

10. A high V.I., detergent lubricating oil consisting essentially of mineral lubricating oil containing between about 1% and about 15% by weight of the metal salt of a hydrocarbon polymer sulfonic acid having between 0.1 and 2.5 equivalents of metal in the form of metal base complexed therewith per equivalent of metal of the sulfonate, said metal of the metal salt and of the metal base being a metal selected from the class consisting of the alkali and alkaline earth metals, and said hydrocarbon polymer being one having a molecular weight of between about 10,000 and about 50,000 and selected from the class consisting of polymers of monoolefins having 3 to 6 carbon atoms per molecule and copolymers of said monoolefins and multiolefins having 4 to 7 carbon atoms per molecule in which the ratio of multiolefin to monoolefin is between about 0.005 and about 0.1 to 1.

11. A lubricating oil according to claim in which said metal of the metal salt and of the metal base is an alkaline earth metal.

12. A lubricating oil according to claim 10 in which said metal of the metal salt and of the metal base is an alkali metal.

13. A lubricating oil according to claim 10 in which said hydrocarbon polymer is an isobutylene polymer having a molecular Weight between about 10,000 and about 30,000.

14. A lubricating oil according to claim 10 in which said hydrocarbon polymer is an isobutylene-isoprene copolymer having a molecular weight of between about 10,000 and about 30,000 in which the ratio of isoprene to isobutylene is between 0.01 and 0.03 to 1.

15. A lubricating oil according to claim 10 in which said hydrocarbon polymer is an isobutylene-butadiene copolymer having a molecular weight of between about 10,000 and about 30,000 in which the ratio of butadiene to isobutylene is between 0.01 and 0.03 to l.

16. A method of preparing a high V.I. detergent lubricating oil which comprises polymerizing an unsaturated hydrocarbon selected from the class consisting of monoolefins having 3 to 6 carbon atoms per molecule and mixtures of said monoolefins with multiolefins having 4 to 7 carbon atoms per molecule, at temperatures between 40 C. and 78 C. in the presence of a Friedel- Crafts catalyst and in the presence of a normally liquid hydrocarbon solvent to produce, a polymer of 10,000 to 50,000 molecular weight, sulfonating the resulting reaction mixture, diluting the sulfonated product with a light mineral lubricating oil, neutralizing the sulfonic acids with a metal base in which the metal is selected from the class consisting of the alkali and alkaline earth metals, removing water and hydrocarbon solvent and adding the resulting oil concentrate to mineral lubricating oil to produce an oil containing 1% to 15 by weight of the polymer sulfonate.

17. A method of preparing a high V.I. detergent lubricating oil which comprises polymerizing an unsaturated hydrocarbon selected from the class consisting of mono olefins having 3 to 6 carbon atoms per molecule, and mixtures of said monoolefins with multiolefins having 4 to 7 carbon atoms per molecule, at temperatures between -40 C. and -78 C. in the presence of a Friedel- Crafts catalyst and in the presence of a normally liquid hydrocarbon solvent to produce a polymer of 10,000 to 50,000 molecular weight, sulfonating the resulting reaction mixture, diluting the sulfonated product with a light mineral lubricating oil, neutralizing the sulfonic acids with a metal base using between 1.1 and 3.5 equivalents of metal base per equivalent of sulfonic acid, the metal of said metal base being selected from the class consisting of the alkali and alkaline earth metals, removing water and hydrocarbon solvent and adding the resulting oil concentrate to mineral lubricating oil to produce an oil containing 1% to 15% by weight of the polymer sulfonate.

18. A method according to claim 17 in which said metal of the metal base is an alkaline earth metal.

19. A method according to claim 17 in which sai metal of the metal base is barium.

20. A method according to claim 17 in Which said metal of the metal base is calcium.

21. A lubricating oil additive adapted to be diluted with mineral lubricating oil to produce a lubricating oil having high V.I. and detergency characteristics, said additive consisting essentially of mineral lubricating oil containing between about 15% and about 50% of an oil-soluble metal salt of hydrocarbon copolymer sulfonic acid, said metal being selected from the class consisting of the alkali and alkaline earth metals and said hydrocarbon copolymer being one having a molecular weight between about 10,000 and about 50,000 and being a copolymer of a monoolefin having 3 to 6 carbon atoms per molecule and a multiolefin having 4 to 7 carbon atoms per molecule in which the ratio of multiolefin to monoolefin is between about 0.005 and about 0.1 to 1.

References Cited in the file of this patent UNITED STATES PATENTS 2,330,900 Loane et al. Oct. 5, 1943 2,361,476 Higbee et al Oct. 31, 1944 2,367,468 Mixon et al. Jan. 16, 1945 

5. A HIGH V.I., DETERGENT LUBRICATING OIL CONSISTING ESSENTIALLY OF MINERAL LUBRICATING OIL CONTAINING BETWEEN ABOUT 1% AND ABOUT 15% BY WEIGHT OF THE METAL SALT OF A HYDROGEN POLYMER SULFONIC ACID, SAID METAL BEING SELECTED FROM THE CLASS CONSISTING OF THE ALKALI AND ALKALINE EARTH METALS AND SAID HYDROCARBON POLYMER BEING ONE HAVING A MOLECULAR WEIGHT BETWEEN ABOUT 10,000 AND ABOUT 50,000 AND SELECTED FROM THE CLASS CONSISTING OF POLYMERS OF MONOOLEFINS HAVING 3 TO 6 CARBON ATOMS PER MOLECULE AND COPOLYMERS OF SAID MONOOLEFINS WITH MULTIOLEFINS HAVING 4 TO 7 CARBON ATOMS PER MOLECULE IN WHICH THE RATIO OF MULTIOLEFIN TO MONOOLEFIN IS BETWEEN ABOUT 0.005 AND ABOUT 0.1 TO 1 